1. Field of the Invention
The invention relates generally to a process for making ultra-fine particles of a high performance polymer; and more specifically to a process for making ultra-fine spherical particles of a high performance polymer in a yield greater than 90%.
2. Description of the Related Art
High performance polymers such as polyetherimide can be made into ultra-fine powders (i.e. having a diameter of less than or equal to 75-microns) by emulsifying the polymer in an organic solvent, and further removing the organic solvent from the emulsion through distillation. Information relevant to such methods can be found in U.S. Pat. No. 6,528,611. However, particles made by such an emulsion distillation process can result in a poor yield of ultra-fine particles. In particular, the yield of ultra-fine particles can be less than 90%. Therefore, there is a need for an optimized process for a higher yield for commercial feasibility.